Naturally occurring waves occur in the ocean and also in rivers. These waves are of various types, such as moving waves which may be of various shapes, including tubular and other breaking waves. A relatively rare type of wave in nature is the standing wave, which has a steep, unbroken and stable wave face. This type of wave can have enough power and velocity to support surfing on the wave face without causing the wave to decay rapidly. This wave, if forced to decay, for example by overly obstructing the flow, reforms naturally when the obstructions are removed. Natural standing waves have been shown to occur where water flows across natural river bed formations, known as anti-dunes. Upon flow over anti-dunes, the water flow rises into a natural standing wave. Natural standing waves occur in the Waimea Bay river mouth of the Waimea River on the Hawaiian island of Oahu, on the Snake River in Wyoming, and several other places.
Surfers are constantly searching for good surfing waves, such as tubular breaking waves and standing waves. There are only a few locations in the world where such waves are formed naturally on a consistent basis. Thus, there have been many attempts in the past to create artificial waves of various types for surfing in controlled environments such as water parks. In some cases, a sheet flow of water is directed over an inclined surface of the desired wave shape. Therefore, rather than creating a stand-alone wave in the water, the inclined surface defines the wave shape and the rider surfs on a thin sheet of water flowing over the surface. This type of apparatus is described, for example, in U.S. Pat. Nos. 5,564,859 and 6,132,317 of Lochtefeld. In some cases, the inclined surface is shaped to cause a tubular form wave. Sheet flow wave simulating devices have some disadvantages. For example, since these systems create a fast moving, thin sheet of water, they produce a different surfing experience to a real standing wave.
In other prior art wave forming devices, a wave is actually simulated in the water itself, rather than being defined by a surface over which a thin sheet of water flows. U.S. Pat. No. 6,019,547 of Hill describes a wave forming apparatus which attempts to simulate natural antidune formations in order to create waves. A water-shaping airfoil is disposed within a flume containing a flow of water, and a wave-forming ramp is positioned downstream of the airfoil structure. In other prior art arrangements, such as U.S. Pat. No. 3,913,332 of Forsman, a wave generator is driven around a circular body of water in order to create waves. This arrangement is also complex and will produce traveling waves, not standing waves.
Apparatus for forming deep water standing waves is described in my prior U.S. Pat. Nos. 6,629,803 and 6,932,541. This apparatus creates waves that simulate natural standing waves. Use of an oblique bed form extending across the width of the channel or two intersecting water flows to create a barreling wave is described in these patents.